RAPID: Eco-evolutionary dynamics of host-parasite interactions in a novel environment

RAPID：新环境中宿主-寄生虫相互作用的生态进化动力学

• 批准号: 2323185
• 负责人: Marianna Szucs
• 金额: $ 4.9万
• 依托单位: Michigan State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-05-15 至 2024-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2323185&HistoricalAwards=false
• 关键词: RAPID; Eco; evolutionary; dynamics; host

Invasive insect pests are best controlled in the long term by parasitoid natural enemies that lay their eggs inside the insect. The eggs hatch and develop into larvae, which feed on the body of the insect host from the inside. Because this is a life-and-death struggle, natural selection acts strongly on the host to evolve to escape parasitism and on the parasitoid to overcome host defenses. When insect pests invade a new region, they usually leave behind the parasitoids that are adapted to attack them. It is expected that in this new, enemy-free environment, evolution could result in an insect host with lower defenses. Host evolution in response to parasites is important because host resistance impacts biological control programs. In these programs, enemies from native ranges are introduced intentionally to control invasive insect pests. When the insect host is once again exposed to its parasitoids, natural selection will once again respond. This study investigates how defense levels of the spotted wing drosophila have changed following its invasion of North America and how those defenses may change following the release of a specialist parasitoid from the native range. In addition to broad implications for biological control, the project promises to yield specific insights into control of spotted wing drosophila, which is a major agricultural pest. Lower resistance of invasive spotted wing drosophila could help biocontrol initially, while increased or geographically variable levels of resistance could render biocontrol less successful or less predictable regionally.This project investigates eco-evolutionary dynamics of host-parasitoid interactions following the release of a classical biocontrol agent, the parasitoid wasp Ganaspis brasiliensis against the invasive spotted wing drosophila (Drosophila suzukii). Contrary to expectations, the resistance of spotted wing drosophila seems to have increased instead of decreased in the invaded range in North America and Europe. This increased resistance may stem from reduced competition and ample resources for spotted wing drosophila in the exotic range, permitting maintenance of high levels of defensive compounds. Preliminary data collected prior to the release of the biocontrol agent show that spotted wing drosophila resistance to parasitism by G. brasiliensis is relatively high but also that it is highly variable with 13-48% of parasitoid larvae being killed by the host. In this project, G. brasiliensis will be released at eight sites in Michigan where there is already baseline data about resistance levels of spotted wing drosophila. Subsequent surveys will permit assessment of any changes in resistance following this release of a co-evolved specialist natural enemy.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

从长远来看，入侵害虫最好的控制方法是通过在昆虫体内产卵的寄生天敌来控制。卵孵化并发育成幼虫，从内部以昆虫宿主的身体为食。 因为这是一场生死攸关的斗争，自然选择强烈地作用于宿主进化以逃避寄生，并作用于寄生生物以克服宿主的防御。当害虫入侵一个新地区时，它们通常会留下适合攻击它们的寄生蜂。预计在这个新的、没有敌人的环境中，进化可能会导致昆虫宿主的防御能力降低。 宿主对寄生虫的反应很重要，因为宿主抗性会影响生物控制程序。 在这些计划中，有意引入来自本地范围的天敌来控制入侵害虫。 当昆虫宿主再次暴露于寄生蜂时，自然选择将再次做出反应。 这项研究调查了斑翅果蝇的防御水平在入侵北美后如何变化，以及这些防御在从本地范围释放专业寄生蜂后可能如何变化。 除了对生物控制具有广泛的影响外，该项目还有望对控制斑翅果蝇（一种主要的农业害虫）产生具体的见解。入侵性斑翅果蝇的较低抵抗力可能有助于最初的生物防治，而抵抗力水平的增加或地理差异水平可能会导致生物防治不太成功或在区域内难以预测。该项目研究了经典生物防治剂释放后宿主与寄生物相互作用的生态进化动力学，寄生蜂 Ganaspis brasiliensis 对抗入侵的斑翅果蝇（Drosophila suzukii）。与预期相反，在北美和欧洲的入侵范围内，斑翅果蝇的抵抗力似乎不降反升。这种抵抗力的增加可能源于外来范围内竞争的减少和斑翅果蝇的充足资源，从而允许维持高水平的防御化合物。在生物防治剂释放之前收集的初步数据表明，斑翅果蝇对巴西果蝇寄生的抵抗力相对较高，但也存在很大差异，13-48%的拟寄生物幼虫被宿主杀死。在该项目中，G. brasiliensis 将在密歇根州的八个地点释放，这些地点已经有关于斑翅果蝇抵抗水平的基线数据。 随后的调查将允许评估共同进化的专业天敌释放后抵抗力的任何变化。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力优点和更广泛的影响审查标准进行评估，被认为值得支持。